[Buildroot] [PATCH] package/skeleton-init-systemd: create a symlink /var/run to ../run

[Romain Naour]

Hi Trent,

Le 23/02/2018 à 19:25, Trent Piepho a écrit :
> On Thu, 2018-02-22 at 23:10 +0100, Romain Naour wrote:
>> As reported by Jérémy Rosen [1] and Jan Kundrát (RO case)[2], systemd
>> looks for the dbus socket in /run/dbus instead of /var/run/dbus which
>> is not where dbus puts the socket. This is a change introduced with
>> the last version bump v237 [3].
>>
>> The file /usr/lib/tmpfiles.d/var.con will create automatically that
>> symlink at bootup /var/run doesn't exist yet. But dbus creates, at
>> install time, the directory /var/run/dbus without taking care of
>> /var/run. So we end up with two different directories /run and
>> /var/run. This bug affects more or less all systemd-provided
>> utilities, including logind and systemd itself.
>>
>> This patch create the correct symlink run -> ../run when systemd
>> is used as init system.
> 
> This doesn't work in the RO root case.

Indeed, but I'm testing/fixing the RW case with this patch
(BR2_TARGET_GENERIC_REMOUNT_ROOTFS_RW).

> I described this in another
> mail to the list, but in the RO root case target/var is a symlink to
> target/usr/share/factory/var.  Thus this link is actually created as:
> 
> target/usr/share/factory/var/run -> ../run

The symlink is only created when BR2_TARGET_GENERIC_REMOUNT_ROOTFS_RW is set.
The RO behavior is left unchanged.

> 
> It points to target/usr/share/factory/run, which is wrong.  In order to
> get it to work in the RO case, instead create this link.
> 
> define SKELETON_INIT_SYSTEMD_VAR_RUN_LINK
>        ln -sf ../../../../run $(TARGET_DIR)/usr/share/factory/var/run
> endef
>  
> SKELETON_INIT_SYSTEMD_POST_INSTALL_TARGET_HOOKS += \
>        SKELETON_INIT_SYSTEMD_VAR_RUN_LINK
> 
> Then you get a target that looks like this:
>                                                                  
> lrwxrwxrwx    1 root     root  29 Feb 23 02:35 /var/run -> ../usr/share/factory//var/run
> lrwxrwxrwx    1 root     root  15 Feb 23 00:51 /usr/share/factory/var/run -> ../../../../run
> 
> On the target, /var/run ends up pointing to /run and also on the host
> $TARGET_DIR/var/run points to $TARGET_DIR/run.
> 

The RO case can be fixed in a follow up patch or you can rework this patch with
your modifications. Maybe Adam can help here.

Adam, you bumped systemd to v237 can you have a look ?

Best regards,
Romain